Motor



Oct. 29, 1940. .1. A. MOULD MOTOR Filed 0911. 11, 1937 2 Sheets-Sh-get 1 1" 1: I"- 26 25 5.019 21 25 27 ea INVENTOR QM AT'rbRNEYa Patented Oct. 29, 1940 UNITED STATES PATENT o'rr ce MOTOR; .l'alnes A. Mould, Milwaukee, Wis. Application October 11, 1937, Serial No. 168,329

\ 20 Claims.

This invention relates to improvements in motors.

The invention is illustratively disclosed in an exempliflcation using pneumatic power for the operation of a vibrator and a percussion tool. It will, however, be apparent from the following disclosure that the invention is applicable to.

motors for any purpose and operating mechanically, pneumatically, hydraulically, electrically, or by steam or internal combustion. In other words, the present invention relates to the motor irrespective of how it is powered or the purposes for which it is used.

The primary object of the invention is to pro- .15 vide anovel and improved. means for. transmitting motion to a free piston for its return stroke. More particularly stated, it is my primary object to provide for the return of a free piston by a means including a relatively powerful steel or pneumatic spring mounted externally ofthe of a motor of the general type specified.

Still another important object of the inven: tion' is to provide novel and improved means whereby a, device of the character described may, whether operated separately or as one of a gang of such devices, be started and stopped independently of other devices without valve .manipulation and from any desired point.

Other objects will appear from the following disclosure. 7 In the drawings:

' Figure 1 is a view in longitudinal section show ing the invention embodied in a vibrator, a portionof the piston being broken awayto expose the relation of the return lever thereto.

Figure 2 a view taken in section on the line 2-2 of Figure l. a a

Figure 3 is a view in longitudinal section showing anembodiment of the invention as applied for the actuation of a percussion tool. Like parts are identifiedby the same reference characters throughout the several views.

In the vibratory motor shownin Fig. 1 the cylinder 4 is provided with an exhaust port at 5 and another port at 6, both communicating directly with the atmosphere. There is also-in the head of the cylinder an intake port at I controlled by a' valve 3 through which air or other" operating fluid is admitted from the supply passage 3 to force the piston l0 toward the right in cylinder 4 as viewed in Fig. l. A cut-oil valve 6 It may control the'supply of air to the valve chamber |2 if desired.

The piston I0 is provided in its side with a cavity at I. The upper surface of this cavity comprises a cam having a substantially radial 1o portion at I6 and aninclined'portion at ll. Coacting therewith is the head l8 of a lever 20 projecting radially from the annulus 2| which is Journaled for rotation in the generally cylindrical housing 22 which may be cast integrally with cyl- 15 inder l with its axis ofiset from, and substantially at rightangles to, the axis of the cylinder.

If any other type of spring were employed, the housing would be diflerently formed and disposed. For the purposes of the present disclo- 20 sure one or. more torsion springs 25 are used, each such spring having one of its ends fixed in the annulus 2| andits other end fixed in one of the closures 26 of the tubularhousing 22.

Journaled in these closures I provide a shaft 21 25 carrying the starting and stopping lever 28.

.ofthis device to the operating fluid .admitted through duct 3 and will thereupon serve to lubricate the valve '8, piston l0, and the rotor 2|, as well as the bearing between the arm or lever 20 and the piston. 40 The periodic pressure reciprocation ofthe pis- I ton on its expansion stroke in this pneumatically operated device as disclosed, is controlled by the valve 8 which is provided with a stem at 38 projecting into the path of the arm or lever 20, tobe engaged by the arm 20 as the piston approaches the top of its stroke, thereby opening thevalve. The valve is normally seated by a compression spring 39 within the/valve chamber |2.

, The valve and its stem therefore constitute, for

the purposes of the present disclosure, a means for timingthe initiation of the expansion stroke of the piston. Obviously, if the device were electrically powered the equivalent timing means might be a switch, or if the device were powered 55' by internal combustion the equivalent timing means might likewise be a switch in the ignition system. In any case, a push rod or stem operated by the arm 28 would be a convenient mode of 5 transmitting motion in timed relation to piston movement.

In Fig 1 I have illustrated the piston at the commencement of its expansion, stroke. Its movement toward this point has been relatively slow as will be evident from the fact that after the piston passed the port 5 in its movement toward the left as viewed in Fig. 1, it began to compress in the head of the cylinder the air or other gases present therein. The proportioning of the parts is preferably such that the pressure in the cylinder head has been built up by the piston to such a point as to prevent any impact between the piston and cylinder head, thus bringing the piston gradually to rest against an air cushion.

As the piston approached the cylinder head, however, the pressure of the air cushion was suddenly augmented by impact of the arm 20 against the valve stem 38, thus opening valve 8. As the parts appear in Fig. 1, the supply air is being admitted to the cylinder and will immediately commence to drive the piston from the head toward the right as viewed in Fig. 1.

At this point the torsion spring is under minimum compression. Its effectiveness on the piston, however, is at a maximum, the arm 20 being substantially at right angles to the piston axis so that for a given rotation of the rotor or annulus '2l there will be a minimum piston movement. Conversely, the described position of the parts will assure that the spring will offer a minimum resistance to piston movement due to the right angle position of lever 20. This is in addition to the fact that the torsion spring is at minimum 40 compression at this time. Collectively these factors-assure speedy piston acceleration under pressure of the air supply communicated through passage 9.

As the piston moves outwardly, the air in the 45 cylinder below the piston will escape through port 6 until finally the piston covers port 8 and,

at about the same time, uncovers the exhaust port 5, whereupon the impelling air will escape through the exhaust port and the air remaining 50 in the end of the cylinder beyond the piston will be trapped by the piston and will form an air cushion to bring it to rest.

In moving toward this position, the piston will be compressing the torsion springs 25. As the 55 piston approaches its extreme position, the head l8 on arm 28 will ride out of the radial portion l6 of the cam slot on to the inclined portion l1 thereof. The eiTect of the rotation of the annulus 2i and arm 20 would normally be to in- 60 crease the angular movement of annulus 2| in proportion to the axial movement df the piston.

Ihis would supplement the increasing torsion of springs 25 to greatly increase the effective resistance to piston movement if it were not for 65 the compensating effect of the angular surface H of the cam slot, the inclination of which is such that a given piston movement will result in a decreasing angular displacement of the rotor 2 I. Thus, although the effective resistance of the 7 spring to piston displacement increases during piston movement, it does not at any time become severe, and the total movement of the spring between its fully compressed and fully expanded positions is kept at a very nominal figure.

7 The compression of gases beyond the piston,

together with the accumulated resistance of the springs, ultimately brings the piston to rest and initiates its return. The return continues under spring pressure after the air pressure is relieved by the fact that the piston clears port 6. The spring is also sufiiciently strong, as above indicated, to compress air in the head of the cylinder after the piston clears port 5.

The relation of the air pressure on valve 8 and the compression spring 39 beyond said valve to the strength of the torsion springs which force the piston toward the cylinder head is, or may be, such that if the piston and arm 20 are brought to rest at approximately the point of contact of the arm with the valve stem 38, the pressure of the springs 25 will be inadequate to force the valve open. In other words, in the preferred construction of the device, the inertia impact of arm 20 on the valve stem is prerequisite to the opening thereof.

This enables me to start and stop the device without manipulating the valve II or any other valve in the air supply line. The feature is of advantage in the event that the motor is located in a relatively inaccessible position, in which case I may connect lines to the openings provided at 40 in the ends of the lever 28. By manipulating the appropriate rope I can engage the lugs 29 and 38 on shaft 21 and annulus 2| in such a way that I can pass through lever 28 and such lugs sufliciently increased resistance to the rotation of arm 28 as to bring the arm to rest before its impact opens the valve 8. In this position the parts will all remain indefinitely at rest, the fact that valve 8 remains closed preventing the escape of air from the device.

When it is desired to restart the apparatus a tug on the rope connected with the right hand end of lever 28 (as viewed in Fig. 1) will cause the member I8 of arm 28 to engage the flat surface 4l of the cam slot IS in the piston to thrust the piston outwardly in the cylinder, thus storing up energy in the spring. When the lever 28 is sharply released, the spring will function to thrust the piston into the cylinder head and the lever 20, now moving with substantial momentum against the valve stem 88, will momentarily open valve 8 to re-initiate the sequence of automatic operations of the device.

The rapid reciprocation of the piston, even without contact with any portion of either end of the cylinder, will set up vibration suflicient to enable the device to be used as a vibrator. For this purpose I provide a bracket 42 with which the remote end closure 43 of the cylinder is connected by means of a. bolt at 44. I provide an ear 45 on the cylinder casting through which another bolt at 48 passes to engage the slotted portion 41 of the brace 48, the latter being pivoted on bolt 48 to the bracket 42. Such a bracket is frequently located on the concrete form to vibrate the form and thereby to assist in vibrating the cement mix therein contained. As above indicated, however, the invention pertains to the motor irrespective of its use.

To illustrate another advantage of this mechanism, where the piston is subject to impact, I have shown in Fig. 3 a different embodiment of the invention as applied to a percussion tool tamper or the like. This device is arranged to function in an upright rather than a horizontal position. The cylinder has a vent port at 5| corresponding to that already described. The other vent 52 is located near the extreme end of the cylinder so that at no time will an air cushion be trapped beneath the piston 66. The cam slot 16 in the side of the piston is identical with that already described, as is the co-action of the lever arm 28 therewith. The rotor 2| and the connec- '5 tion of the torsion springs thereto within the housing 22 is likewise identical with the disclosure of Fig. 2. The starting and stopping shaft 21 carries the same lug '29 cooperating with lug 38 on the rotor 2i for the purposes already specified l operated from a distance, I have shown a single lever at 66 designed for-local manual manipulation.

The head of the cylinder casting has two handles at 61 and 58, the latter providing the air passage 58. Above this is disposed the oil reservoir 68, the top of which is subject to air pressure through duct 8| and the bottom of which discharges into the air passage through duct 62 under the control of the needle valve 63.

The poppet valve 8 and its stem 38 function in exactly the manner already described.

At its lower end the cylinder 60 carries an extension at 65 constituting a guide and mounting for the percussion or tamping tool 66. This tool may be inserted by removing the closure-61 and the cushion 68 of rubber or the like which, in-operation, is engageable by the flange 69 of tool 66. The head portion I0 of tool 66 projects through the guide casting 66 intothe path of piston 55 to receive the impact thereof.

I have found that if the return spring of a piston such as that shown at 55 is directly sub- J'ect to impact it tends to become crystallized. I have found, moreover, that this tendency is minimized if the angularity of the cam surface I1 is such that at the moment of impact the arm 20 has a sliding rather than a direct thrust engagement with=the piston. Naturally, the angu- 40 larity of surface l'l cannot be increased too greatly toward parallelism with the piston axis or thesprings will not be able to initiate the return of the piston. The approximate angle shown has, however, been found to operate .very successfully in motors of this type. Thus, in percussion tools, there is this additional advantage in the inclination of the cam surface H.

The starting and stopping of the device shown in Fig. 3 is accomplished exactly in accordance with the disclosure of Fig. l and Fig. 2. It will occasion no harm to the operator to pull the lever 66 sufficiently to engage the lugs 29 and 38 and thereby to resist the compression stroke of the piston. The same is true where the device is powered by internal combustion instead of by a compressed fluid. The operator merely absorbs the-slight impact remaining in the piston near the end of its compression stroke, and this is sufficient to bring the piston to rest. Where the device is powered by internal combustion,.the

starting'lever is used to restart it in exactly the same manner in which it operates where the power is derived from the compressed fluid. The

connection to the piston being a loose oonnection to the oscillatoryannulus 2| or'equivalent means of storing energy temporarily for piston return, such connection alsoserving to operate -75 valves or the like and to permit of the use of a but, inasmuch as this device will not ordinarily be starting or stopping device. The fact that the piston is free is particulary apparent from an inspection of the relative positions of the parts as shown in Fig. .3.- The angular position assumed by the arm 28 at the extreme of its movement is ideally suited to applicants objectives as above described, but would not be as suitable if useful work were transmitted through said arm.

I claim:

1. In a device of the charaoterdescribed, the

combination with a cylinder and a piston reciprocable therein,.of resilient energy storing means outside of the cylinder for the return of the piston in one direction of reciprocation therein, a loose connection through a side of the cylinder from said means to the piston, said piston and connection including means for decreasing the response of said energy storing means in proportion to piston movement as energy is stored, whereby said piston is measurably free to overrun said connection in its other direction of reciprocation, mechanism for causing the reciprocation of the piston in the cylinder in opposition to said means, and means for operating said mechanism in timed relation to piston movement.

2. In a device of the character described, the

combination with a cylinder closed at its ends and provided at an intermediate portion of'its wall with a slot, of a piston reciprocable therein "and having a working face at one end and adapted at the other end for at least partial compression, piston actuatingmeans extending through the slot of the wall and in operative engagement with the piston, spring means disposed external- 1y of the cylinder and connected with said actu- :ating means for the actuation of said piston tocombination with a cylinder. of a piston provided with a cam in its side, the side of said cam nearest the piston head being substantially radial at its inner end and'thence extending on an inclination toward said head, of a piston return member mounted for oscillation externally of said cylinder and adjacent the path of piston reciprocation, an arm'connected with the memberand engaged with said cam, the oscillatory axis of the member being so located transversely with respect to the axis of the cylinder that said arm will extend substantially at right angles' between the member and the piston when the piston is adjacent one extreme of its reciprocation in the cylinder. the arm at the other extreme of reciprocation of the piston being parfss tially withdrawn from said slot along the inclined portion thereof, and means actingon said member in resilient opposition to the movement of said piston from the first mentioned position to the last mentioned position.

4. In a device of the character described, the combination witha cylinder and a piston re- Y 'ciprocable therein, of "means for causing fluid pressure to act periodically on the piston head to force the piston in one direction, means disposed externally of the cylinder opposing said fluid pressure and adapted yieldably'to return said piston, and manually operablemechanism opcratively connected with said means and adapted on engagement by the operator to control the starting and stopping of the cyclic operation of the piston.

5. In a-device of the character described, the combination with a cylinder and a piston mounted for cyclic reciprocation therein, of means for the controlled introduction and release from the cylinder of fluid for piston operation in one direction, means, disposed externally of the cylinder and operatively connected with the piston for the return thereof in the opposite direction, said means including a resilient energy storing device, and manually operable mechanism normally disconnected from said means and engageable therewith in opposition to said device, whereby to be adapted either to interrupt or to initiate the cyclic reciprocation of the piston.

6. In a device of the character described, the combination with a cylinder provided with fluid intake and exhaust ports and .a free piston arranged for cyclic reciprocation in the cylinder under fluid pressure, of mechanism for timing the pressure actuation of the piston in one direction in the cylinder, a spring disposed externally of the cylinder, means including an arm acted on by said spring and extending through the cylinder into operative connection with the piston for the actuation thereof to return the piston in opposition to such fluid pressure, said timing means having a portion disposed in the path of said last mentioned means to receivemotiontherefrom in the course of piston return, andamanually operable starter engageable with said last men tioned means in a direction to impel said piston for the initiation of its cyclic movement.

7. In a device of the character described, the combination of a cylinder having intake and exhaust ports and a piston mounted for free cyclic 4 reciprocation in the cylinder under the pressure of a fluid admitted through the intake port, of

' means for piston return in opposition to the direction of fluid actuated movement, said means comprising a rotor mounted externally of the 45 cylinder, an arm connected to the rotor and projecting laterally through the cylinder into operative connection with the piston, the piston wall having a cam slot to receive the end of said arm, a torsion spring acting on the rotor in a 50 direction for piston return, and a starting lever mounted for rotation substantially coaxially with the rotor, said starting lever and rotor having normally disengaged lugs manually engageable 'in a direction opposed to the return of said pis- 55 ton.

8. In a device of the character described, the combination of a cylinder having intake and exhaust ports and a piston mounted for free cyclic reciprocation in the cylinder under the pressure 60 of a fluid admitted through the intake port, of

means for piston return in opposition to the direction of fluid actuated movement, said means comprising a rotor mounted externally of the cylinder, an arm connected to the rotor and pro- 65 jecting laterally through the cylinder into operative connection with the piston, the piston wall having a cam slot to receive the endof said arm,

a torsion spring acting on the rotor in a direction for piston return, and a starting lever mounted 70 for rotation substantially coaxially with the rotor,

said starting lever and rotor having normally disengaged lugs manually engageable in a direction opposed to the return of said piston, the axis of said rotor being so located that said arm ap- 75 proaches a position at right angles to the axis of piston in approaching the other extreme of its movement.

9. In a device of the character described, the" combination of a cylinder having intake and exhaust ports and a piston mounted for free cyclic reciprocation in the cylinder under the pressure of a fluid admitted through the intake port, of means for piston return in opposition to the direction of fluid actuated movement, said means comprising a rotor mounted externally of the cylinder, an arm connected to the rotor and projecting laterally through the cylinder into operative connection with the piston, the piston wall having a cam slot to receive the end of said arm, a torsion spring acting on the rotor in a direction for piston return, and a starting lever mounted for rotation substantially co-axially with the rotor, said starting lever and rotor having normally disengaged lugs manually engageable in a direction opposed to the return of said piston, the axis of said rotor being so located that said arm approaches a position at right angles to the axis of the piston in approaching the position of maximum compression in said cylinder, whereby said arm will be sharply inclined to the axis of the piston in approaching the other extreme of its movement, and means having a portion disposed in the path of said arm for timing the initiation of fluid induced movement of said piston.

10. In a device of the character described, the combination with a cylinder and a piston mounted for cyclic reciprocation therein, of means for the controlled introductipn to and release from the cylinder of fluid for piston operation in one direction, said means including displaceable mechanism for timing the initiation of such operation, a spring opposing displacement of said mechanism, a piston return means disposed externally of the cylinder and provided with an operative connection through the cylinder with the piston for the return thereof in the opposite direction, said return means including a return spring in which energy is stored by the fluid actuated movement of the piston in said first direction, and manually operable mechanism for the manipulation of said return means in starting and stopping the piston, the spring opposing displacement of said timing mechanism being sufliciently strong with reference to the spring comprised in said return means to require that the return means have momentum as a prerequisite to the displacement of said timing mechanism, whereby the piston will remain at rest when said manually operable mechanism deprives said return means of momentum before said timing mechanism is displaced.

11. In a device of the character described, the combination with a cylinder and a piston mounted for cyclic reciprocation therein, of means for the controlled introduction to and release from the cylinder of fluid for piston operation in one direction, said means including displaceable mechanism for timing the initiation of such operation, a spring opposing displacement of said mechanism, a piston return means disposed externally of the cylinder and provided with an operative connection through the cylinder with the piston for the return thereof in the opposite direction, said return means including a return spring in which energy is stored by the fluid actuated movement of the piston in said first direction, and manually operable mechanism for the manipulation of said return means in starting and stopping the piston, the spring opposing displacement of said timing mechanism being sufliciently strong -with reference to the springcomp'ressed in said return means to require that the return means have momentum as a prerequisite to the displacement of said timing mechanism, whereby the piston will remain at rest when said manually operable mechanism deprives said return means of momentum before said timing mechanism is displaced, said manually operable mechanism being normally disconnected from said means and engageable therewith in opposition to the direction in which the spring actuates said return means to return said piston. I

12. In a device of the character described, the combination with a cylinder and a piston reciprocable therein, of means for the timed introduction of a fluid into the cylinder for the cyclic operation of the piston therein in one direction of reciprocation, resilient energy storing means out-- side of the cylinder for the return of the piston in the opposite direction of reciprocation, and a loose connection through a side of the cylinder from said resilient means to the piston; said connection including means permitting lost motion for accommodating relative overrun of said piston with respectto said energy storing means.

13. In a device of the character described, the combination with a cylinder and a piston mounted for cyclic reciprocation therein, of means for the controlled introduction and release from the cylinder of fluid for piston operation in one direction, of energy storing means outside of the cylinder for resiliently storing up energy on the outward stroke for the, return of the piston, on

the inward stroke, said means having a mechanical connection through the cylinder with the pistonand said connection including mechanism for reducing the travel oi. said means in proportion to the stroke of the piston.

14. In a device of the character described, the

combination with a cylinder and a piston pro-.

vided with a cam and mounted for cyclic reciprocation therein, of means for the controlled intake and release from the cylinder of fluid for the operation of the piston in one direction,- resilient energy storing. means for the 'retum ofthe .piston on the inward stroke, and mechanism for varying the rate of travel of said resilient means as compared with the piston at different "portions of the piston stroke, said mechanism operatively connecting the piston with said resilient means to store energy therein during the outward piston stroke and to deliver such energy to the piston during the inward stroke.

15. In a deviceof the character described, the I combination with a cylinder and a piston mounted for cyclic reciprocation therein, of means for the controlled introduction and release at a portion of the cylinder beyond one end of said piston of fluid for piston operation in one direction,

means for the return of the piston in the opposite direction, and a starting and stopping handle disposed externally of the cylinder and provided.

with an operative motion transmitting connection through the side oi the cylinder to the side of the piston, whereby the operator can initiate or stop piston reciprocation by manipulation of.

said handle without access to the portion or the cylinder to which such fluid is admitted.

16. In a device of the character described, the combination with a cylinder and a piston mounted for cyclic reciprocation therein, of power means for actuating the piston in one direction, resilient means for returning the piston in the opposite direction, and a -starting and stopping handle comprising an oscillatory member mounted at the side of said cylinder and having a lost motion connection to the piston including a' part from which the piston is normally freely movable and which is engageable for motion transmission to the piston on manipulation of the handle in a direction opposing the return oi; the piston.

17. In a device 01 the character described, the combination witha cylinderhaving a compression space and means for introducing and releasing a motive fluid to and from said space, of a piston reciprocable in the'cylinder to and from said space-a: piston return device comprising a spring having a mechanical connection to said piston externally of said space, and a handle having a lost motion mechanism engageable with said connection in opposition to'said spring upon manipulation of the handle.

18. In combination, a cylinder having an apertured side wall, a piston reciprocable in the cylinder, a rotor adjacent the cylinder having an arm extending through said wall and operatively connected to the piston, a handle mounted for movement adjacent the rotor and normally free of movement therewith, and a spring operatively connected to receive energy irom'said piston in one direction of piston reciprocation for its return in" the opposite direction, said handle and rotor having complementary parts engageable in opposition to the return of said piston on manipulation of the handle.

19. In an engine, the combination, with a cyl- 4 I inder and a piston reciprocable in the cylinder upon an expansion stroke and a compression stroke, of an oscillatory return device operativelyconnected with the piston and having a part exposed externally oi the cylinder, a torsion spring mounted externally oi the cylinder, and operatively connected with said part for the movement thereof in a direction to return said piston upon its compression stroke, means for initiating movement of -the,piston on its expansion stroke in opposition to said spring, and timing mechanism operatively connected with said means to control the functioning there'of and inlatory piston return device to be actuated there'- by near the completion of, the compression stroke of the piston. m

, 20. In an engine, the combination with a cylcluding a part disposed in the path of said oscil inder and a piston, oi a spring mounted on the outside cf the cylinder, a piston return means in operative connection with the spring and the pis- -ton for returning the piston toward one end of the cylinder; means for efiecting-the advance of the piston against the spring from said last menthe spring actuated piston retumrneans for controlling the initiation pi piston-advance against 'tioned cylinder end, and timing mechanismror controlling said last mentioned means and'operatively disposed to be actuated by the motion of. 

